Perl getsockopt()函數

perl getsockopt()函數，getsockopt()函數學習例子，getsockopt()函數實例代碼，getsockopt()函數教學等

語法

getsockopt SOCKET, LEVEL, OPTNAME

定義和用法

獲取套接字選項SOCKET套接字實現的選項OPTNAME級彆LEVEL。在下表中給出一些的樣例值用於OPTNAME一個套接字級彆

OPTNAME 	Result SO_DEBUG 	Get status of recording of debugging information
SO_REUSEADDR 	Get status of local address reuse
SO_KEEPALIVE 	Get status of keep connections alive
SO_DONTROUTE 	Get status of routing bypass for outgoing messages
SO_LINGER 	Get status of linger on close if data is present
SO_BROADCAST 	Get status of permission to transmit broadcast messages
SO_OOBINLINE 	Get status of out-of-band data in band
SO_SNDBUF 	Get buffer size for output
SO_RCVBUF 	Get buffer size for input
SO_TYPE 	Get the type of the socket
SO_ERROR 	Get and clear error on the socket
TCP_NODELAY     To disable the Nagle buffering algorithm.

到底在包中的字符串是什麼，取決於LEVEL和OPTNAME， 詳細信息，請谘詢您的係統文檔。

返回值

• 在標量上下文的錯誤返回undef，否則選項值。

實例

試試下麵的例子：如果使用Nagle算法上打開一個socket，這將檢查：

#!/usr/bin/perl
#by www.gitbook.net

use Socket qw(:all);

defined(my $tcp = getprotobyname("tcp"))
   or die "Could not determine the protocol number for tcp";
# my $tcp = IPPROTO_TCP; # Alternative

my $packed = getsockopt($socket, $tcp, TCP_NODELAY)
   or die "Could not query TCP_NODELAY socket option: $!";
my $nodelay = unpack("I", $packed);

print "Nagle's algorithm is turned ", $nodelay ? "off\n" : "on\n";